1. Field of the Invention
The present invention relates to a portable heating device and more particularly to a novel forced hot air stream generating device. The unit is highly mobile and portable with a quick response time for a wide variety of uses such as drying freshly taped dry wall, roofing installations and other applications where a variable amount of flameless heat may be needed at a location where it would be otherwise difficult to direct heat.
2. Description of the Prior Art
There are a wide variety of space heaters available for different uses. Those skilled in the art, as in the building industry for instance, are aware of the difficulties in bringing heat to bear in various locations on construction sites and the like. Sometimes the locations are difficult to reach, are at a distance from an electrical outlet, or the heating equipment may be too heavy and cumbersome for convenient moving to the desired spot. Many times the heating equipment is needed in a location which cannot be reached unless the heating device can be carried by a worker. Frequently the heating equipment is simply too heavy.
Among the prior art patents of which applicants are aware, are U.S. Pat. Nos. 4,726,767 to Nakajima, 5,155,925 to Choi and 5,009,592 to Roldan et al. These patents disclose hot air blowing devices, as for instance hair dryers, which are hand held and self contained in that they carry their own liquified gas supply for heating the air as well as dry cell batteries for driving a small fan. The patented devices also use an ignition feature to light the gas. The devices disclosed in these patents are, however, structurally and functionally different from the present invention.
U.S. Pat. Nos. 5,156,542 to Harmen et al and 5,344,314 to Zagoroff et al are examples of hand held gas fired heat guns using barrel type mixing chambers with spark ignition features. These devices, however, rely upon the combustible-gas pressure to entrain air into the main mixing chamber or to power a turbine-compressor and are therefor distinguishable from the present invention.
U.S. Pat. No. 3,883,290 to Windelbandt shows a heating device which is used for shrinking plastic films and other applications. It has a burner head 3 with conduits or orifices 12 through which gas from line 5 is directed to the area just in front of the burner. The gas is completely combusted within a short distance of the burner. As with the devices discussed in the preceding paragraphs, this device is small and intended, as can best be determined form the disclosure, primarily as a small hand held heating apparatus for shrinking plastic wrapping films.
U.S. Pat. No. 4,005,976 to Rombach et al is a device intended to be used as a rodent exterminator. This is a gas fueled apparatus which has a frame support 15 for supporting its parts. The specific structure of the barrel may not preclude the device from being utilized in other applications, but the stated purpose is to place the muzzle of the barrel in the burrow of a rodent. Raw air and gas mixture is injected into the burrow and ignited to kill the varmints. The manner of use and design principles of this device are not anticipatory of the present invention.
The Allen heating device in U.S. Pat. No. 2,780,218 has a purpose similar to that of applicants herein, but structurally is significantly different. Air is delivered from blower 34 through hollow handle 12 to the main barrel assembly or casing 10. Air is directed between the concentric tubes and into the burner tube 44. A flame arrester 100 is provided at the outer end of the burner tube 44 so that open flames do not issue from the device. The device is intended to be portable so that it can heat different spaces and be used for different purposes.
U.S. Pat. No. 3,112,742 to Merz is a device designed to burn weeds. It is important to note in column 4, lines 33 to 37 that it is intended to eject flame outwardly form and beyond nozzle 12. This device, while having some features of the present invention, produces flame outwardly of its barrel to achieve an intended purpose. The structural combination of parts together with the design purpose of the device are of interest only.
Other references considered to be of interest only are the following U.S. Pat. Nos.
2,077,043--Genrich PA1 2,788,959--Sherwin PA1 2,896,933--Barnes PA1 2,985,438--Prowler PA1 3,306,335--Myers PA1 3,211,439--Fahlberg PA1 3,301,308--Briggs PA1 3,319,947--Truesdell PA1 3,593,969--Smithson et al PA1 4,848,313--Velie
The above cited references do not solve the problems associated with the need for a portable heating unit or disclose apparatus anticipatory of the present invention.